Rotary desalting device

ABSTRACT

The rotary desalting device relates to a machine for purifying or concentrating fluids containing dissolved materials. The rotary desalting device of the present invention utilizes one or more high speed, thin rotating discs as heat transfer surfaces between a boiling and condensing fluid. The disc or discs are rotated at such high speed that the extreme centrifugal force of hundreds of times the force of gravity reduces the insulating water film to a micro-thin liquid film wherein greatly improved heat transfer coefficients are obtained. Provided in the rotating disc chamber housing is a centrifugal liquid seal to separate the boiling and condensing chambers which is combined with a naturally pressurized fluid discharge at the disc periphery. The rotary desalting engine of the present invention also incorporates other unique and novel components such as an easily cleanable tri-liquid counter-flow spiral heat exchanger and degasser devices to prevent dissolved gas from accumulating in and blocking the purifying system.

United States Patent [191 Schnitzer Sept. 9, 1975 Primary Examiner-LloydL. King Attorney, Agent, or FirmHubbard, Thurman, Turner & Tucker [57]ABSTRACT The rotary desalting device relates to a machine for purifyingor concentrating fluids containing dissolved materials. The rotarydesalting device of the present invention utilizes one or more highspeed, thin rotating discs as heat transfer surfaces between a boilingand condensing fluid. The disc or discs are rotated at such high speedthat the extreme centrifugal force of hundreds of times the force ofgravity reduces the insulating water film to a micro-thin liquid filmwherein greatly improved heat transfer coefficients are obtained.Provided in the rotating disc chamber housing is a centrifugal liquidseal to separate the boiling and condensing chambers which is combinedwith a naturally pressurized fluid discharge at the disc periphery. Therotary desalting engine of the present invention also incorporates otherunique and novel components such as an easily cleanable tri-liquidcounter-flow spiral heat exchanger and degasser devices to preventdissolved gas from accumulating in and blocking the purifying system.

[ ROTARY DESALTING DEVICE [75] Inventor: Emanuel Schnitzer, Houston,Tex. [73] Assignees: H. B. Zachry Company, San

Antonio; Frontier Engineering Corporation, Houston, both of Tex. partinterest to each [22] Filed: Dec. 26, 1973 [2l] Appl. No.: 427,793

Related US. Application Data [63] C0ntinuationin-part of Ser. No.252,202, May ll,

l972, abandoned.

[52] U.S. Cl. 239/223 [5 1] Int. Cl B05!) 3/10; 844d 5/10; F23d/l 1/04[58] Field of Search 239/223, 224; 202/l76, 236

[56] References Cited UNITED STATES PATENTS 2,869,]75 l/l959 Ebhinghousc239/224 2.902123 9 1959 Nyrop 239/223 2,9l7,24l 12/1959 Waldrum. 239/223$346,192 ll/l967 Hegc 239/223 L I L] III/l/l/l/I/ PATENTEU EP M975 sum 1[IF 4 ROTARY DESALTING DEVICE CROSS REFERENCE TO RELATED APPLICATIONThis is a continuation-in-part application of Ser. No. 252.201 filed Mayll. l972. entitled Rotary Desalting Engine. now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention is directed to a rotary desalting device for purifying and/orconcentrating fluids containing dissolved materials which utilizes oneor more high speed. thin rotating discs as a heat transfer surfacebetween boiling and condensing fluids. More specifically. the presentinvention is directed to a rotary desalting device wherein thin rotatingdiscs are attached to a rotating hub capable of being rotated at suchhigh speeds that the centrifugal force is hundreds of times the force ofgravity causing the liquid on the rotating discs to be reduced to amicro-thin liquid film. In its more specific aspects. the rotarydesalting device of the present invention may be used to convert seaWater. brackish water. or polluted fresh water into potable water.

2. Prior Art The following US. patents were cited in the parentapplication:

llsrjon 1.734.013 .l3h 7tl7 LIIIIHZH 199K439 RQINLUSU ZJUXJIUH 2,999.7963.182.793 2.349331 (icrnian 62112} Currently available rotary stilldesigns have the fol lowing disadvantages as compared to the device ofthe present invention.

Latham. Jr. US. Pat. No. 2.469.122. employs a trifluid counter-flow heatexchanger formed of concentric tubing in a helical spiral. This physicalembodiment, however. cannot be disassembled for cleaning of corrosionand salt deposits.

Hickman. US. Pat. No. 2.734.023. utilizes a conical disc designsupported from a cantilevered shaft. Because of the conical disc design.this conical disc must be quite thick since the disc supportsperipherally a second disc to form a condensing chamber between thediscs and/or supports peripherally axial flow compressor blades. whichlimits the operating speed as dis closed in Hickman to about It) timesthe force of gravity. Further. because the disc is supported from acantilevered shaft with varying amounts of water. salt depos its andcorrosion produced cover the inner perhiphery of the rotating condensingchamber; further. the disc is difficult to balance both initially andafter some extended operation. which limits the operating speed. so thatas claimed. only about l(J times the force of gravity is achieved forthe liquid film on it. This film is not reduced in thickness as much asit possible for the higher rotational speeds. The combination of a thickdisc and a thick liquid film results in reduced heat transfercoefficient across the disc, which. in in turn. requires greatercompressor power and reduces the competitive capability of the machine.The lower operating speed produces a much thicker liquid film on thedisc which results in a reduced heat transfer coefficient across thedisc as compared to the device of the present invention For the closedellipsoidal rotating shell design of Hickman. where the slope of thewalls near the periphery approach parallelism with the rotational axis.corrosion and salt deposit collection result in a more severeunbalancing problem. disassembly for cleaning is difiicult for aprecision balance high speed rotor, the lower centrifugal force becauseof the inclined slope near the rim causes longer angular rotationalcontact with the fluid which results in spinning up the fluid to thedisc velocity and a resultant power penalty. and heat transfer isreduced with the thicker liquid film combined with the absence ofrelative shear velocity between the liquid film and the near peripheryof the ellipsoid. In addition, for the multi-staged ellipsoid. thedeletion of a center bearing in order to accommodate the internalplumbing requires a thicker walled ellipsoid for structural supportand/or intensifies the unbalance problem.

Hickman. US. Pat. No. 2.894.879. utilizes a liquid seal between vaporchambers at different pressures. but since this seal is oriented suchthat only one times the force of gravity is exerted on the liquid. it isonly capable of sealing against small pressure differences.

Hickman. US. Pat. No. 2.899.366. utilizes a degassing system vvhichcompromises the system efficiency by discharging energy carrying vaporfrom the system with the dissolved gases.

Tidball. Ll.S. Pat. No. 3.282.798. utilizes a rubbing mechanical sealwhich absorbs energy through the work of friction.

In general. while some of the above patents include components similarto the present invention. none of the devices disclosed have beenoptimized as a system to include the right combination of components.structural design, thermal design. and fluid circuits for maxi mumefficiency operation to render them competitive to other means ofproducing potable water.

There is no known currently available sea water purification unit that.when reduced to a size suitable for residences. hotels or smallindustrial plants. is sufficiently efficient and inexpensive to buy.operate and maintain to be competitive with other potable waterSULIICCS,

SUMMARY OF THE INVENTION The present invention is directed to a rotarydesalting engine which utilizes one or more thin. rapidly rotatingdiscs. The rotating disc or discs act as heat exchange surfaces whichsurfaces extend essentially perpendicular to the hub and axes ofrotation. Further. the rotating discs form condensing and evaporationchambers within the rotating disc chamber housing. The operating speedof the thin. rapidly rotating disc produces a centrifugal force of up toseveral hundred times the force of gravity and results in a high liquidsheer velocity Thus. the film of liquid on the rotating disc ismicrothin. The rotating disc is sealed at its peripheral extremities bythe liquid which comes from each side of the rotating disc with the discspinning partially immersed in the liquid. causing the liquid to behaveas a very heavy fluid and to seal the disc periphery against a highpressure differential. In its more specific aspects. the presentinvention has a design unique to the rotary dcsalting device to maximizethe conservation of energy while producing a design of simpleconstruction and maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is one possible embodiment ofthe rotary desalting device of the present invention;

FIG. 2 is one embodiment of the disc seal;

FIG. 3 is a second embodiment of the disc seal;

FIG. 4 is a degasser device specially adapted to handle the inlet fluidto be purified;

FIG. 5 is a degasser device specially designed to bandle the purifiedfluid;

FIG. 6 is a second embodiment of the rotary desalting device of thepresent invention;

FIG. 7 is an embodiment of the seal disc of the device of FIG. 6-.

FIG. 8 is a cross-section of the rotating disc of the device of FIG. 6;and,

FIG. 9 is a cross-section of a mid-disc distributor on the rotating discof the device of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotary desalting device orengine of the present invention is specifically designed for purifyingor concentrating fluids containing dissolved materials. The

rotary desalting device utilizes one or more high speed.

thin rotating discs as a heat transfer surface between a boiling and acondensing fluid utilizing a vapor com pression distillation concept.The device of the present invention may be used to purify liquids suchas converting sea water. brackish water, or polluted fresh water. intopotable water. The device may further be used to purify for recycling.process chemicals, or process water in industrial plants. Alternatively.the device may be used to concentrate fluids such as film developers.nuclear wastes, or other expensivcly separated material, which can bepurified or concentrated such that they can be either reused or stored.

To describe the present invention, and a specific operation. namely thedesalination of sea water, and referring particularly to FIG. 1. arotary desalting device or engine I is comprised of one or more rotatingdiscs 2 which are mounted on and driven by a hollow drum 3 which is thehub in the rotating disc chamber housing 4. The hollow drum 3 which issealed at one end is attached to an armature shaft 5 of a drive motor 6.The

armature shaft 5 also drives a gear train 7 which in turn drivescompressor fans of the compressor 8. In this embodiment. the gear train7 and compressor 8 are between the drive motor 6 and the rotating discchamber housing 4.

As shown in the embodiment of FIG. 1. there are two rotating circulardiscs 2 mounted on and driven by a hollow drum 3, which forms twoevaporation chambers 10 and II. respectively. with a single condensingchamber 12 between the two discs 2. Hollow drum 3 passes through scaledbearings 13 and 14 which are positioned in the pressure tight rotatingdisc chamber housing 4. The hollow drum 3 is connected and keyedintegrally to the armature shaft 5 by means of a spider 15 at one end ofthe hollow drum 3.

In this embodiment. the rotating shaft 5 is an armature shaft of anelectrical induction motor. An induction type of electric motor ispreferred because of the capability of its field to operate at boilingwater temperatures permitting its bar-wound armature to operate at veryhigh temperatures without burning out. This is not possible with wirewound rotor types of motors.

Also. brush type motors do not possess the required long life capabilityfor dcsalinization that the induction motor possesses, especially athigh temperatures. If ad ditional heat is required, it can be suppliedby electricity. or by burning fuel. It is to be understood that therotating shaft 5 may be driven by electrical motors, combustion motors.or in large design. even a jet engine. The motor 6 drives the shaft 5which rotates in the bearing members 16 and I7 mounted in the housing I8of the motor 6. The shaft 5 may pass through one or more other bearingmembers. but is supported at its other end and passes through bearing [9located at the opposite (sealed) end of the hollow drum 3 from thespider 15.

Sea water is drawn into the rotary desalting engine 1 through the intakestrainer 20 which may consist of a perforated chamber, screen, orparticle bed filter. to remove any solid material carried in with thefluid. From the intake strainer 20, the sea water passes through thetube 21 to the pre-treatment chemical filter 22. The pretreatmentchemical filter 22 may contain chemicals to prevent corrosion of themachine. remove objectionable taste or odor. or remove dissolved orsuspended material that the process will not remove. From the filter 22,the sea water goes through the tube 23 to a liquid phase degasser 24.The details of the liquid phase degasser 24 will be set forthhereinafter. In this embodiment. the sea water is then passed throughtube 25 into the inlet 26 of pump 27. The pump 27, as shown in FIG. 1,is mounted to the sealed end of the rotating disc chamber housing 4 atthe sealed end of the rotating hollow drum 3. The shaft 5 passes throughthe bearing 19 and has keyed integrally thereto a water pump impeller28. The sea water is pumped by the water pump impeller 28 through thetube 29 to a vapor phase degasser 30. the details of which will be setforth hereinafter. The sea water acquires a small temperature increasein the vapor phase degasser 30 and passes through tube 31 into atri-fluid counter-flow heat exchanger 32. The sea water is heated tonear its boiling temperature in the heat exchanger 32 wherein it is thenpassed out of the heat exchanger by tube 33 into a liquid jacket 34which surrounds the motor 6. Waste heat from the motor 6 is conserved inthis embodiment not only by the shaft energy of the drive motor. butalso its waste heat, and the heated sea water is removed from the liquidjacket 34 by tube 35, providing maximum conservation of energy. This isone of several instances in the present invention where conservation ofenergy is achieved and the utilization of energy is made at the level atwhich it is available. The heated sea water flows through thethermostatic valve 36 which maintains the operation temperature atdesign level. and may be used to reduce the initial water flow topromote start-up heating. Hence. the valve 36 provides for automaticstart-up and for stable operation at design temperatures in spite of rawfeed fluid temperatures changing with changing seasons. purified fluiddemand or otherwise.

The flow of the sea water up to this point has all been designed topreserve conservation of encrgyby utilizing all waste heat andcnergy inthe system. and to optimize the system to its maximum. For thepurification of sea water to become commercial. the system must beeconomical and must be optimized to make the device of simpleconstruction and maintenance and sufficiently efiicicnt in its operationto be competitive even in small sizes.

For sea water purification, current desalinization machines must beextremely large and expensive to achieve economical operation. They mustoperate at very high pressures requiring sophisticated and expensiveequipment, or use membranes or microtubes which are difficult to cleanor expensive to replace. For concentrating fluids, membrane filtrationequipment currently available for separating solutions is limited tolight concentrations of dissolved chemicals. Currently available rotarystill designs have disadvantages as compared to the proposed embodiment.

From the valve 36. the sea water flows through the tube 37 into the discchamber housing 4 to a spray ring 38 in the evaporation chamber 10. Thespray ring 38 has a number of nozzles of injector plate arrangements tospray the sea water against one of the rotating discs 2 mounted on thedrum 3. Alternatively, the sea water may be flowed onto the discs 2. Thesea water is sprayed as a fine mist due to the size and number of thenozzles in the spray ring 38. The temperature of the side of the disc 2in the evaporation chamber is higher than the boiling point for seawater, at the pressure existing in the chamber 10. and accordingly, someof the sea water is converted to steam which passes through the openings39 in the hollow drum 3. The remaining sea water on the disc 2 becomes amore concentrated brine" solution. Because of the centrifugal forceimparted to the brine solution, as it approaches the rotation velocityof the disc 2, the brine solution is slung toward the periphery of thedisc 2. The brine solution slung off the disc 2 flows into and fills oneof the annular brine channels 40 in the rotating disc chamber housing 4.The brine solution is removed from the brine channel 40 by a tangentialorifice 41 and is taken by the tube 42 to a second spray ring 43. Thebrine solution which is under pressure from the rotational velocityimparted to it from the disc is sprayed on the evaporation side of thesecond of the discs 2 in evaporation chamber ll. This second evaporationeffect operates similarly to the first effect previously described. Thetemperature of the side of the disc in the evaporation chamber ll beinghigher than the salt water boiling point at the pressure existing inchamber 11 results in some of the water being converted to steam whichenters drum 3 through the openings 44. A higher concen trated brine isslung off of the second disc 2 into a concentrated brine channel 45. Thehighly concentrated brine is removed from the brine channel 45 by atangcntal orifice 46 and passed through the tube 47 into the tri-fluidcounter-flow heat exchanger 32. The hot brine is cooled in the heatexchanger 32 and is removed from the heat exchanger 32 by tube 48wherein it is passed through venturi 49 to a brine outlet 50. Although adual effect design is presented above, an alternative single effectembodiment is compatible with this machine by connecting spray rings 7|and 43 in parallel to valve 36 and connecting brine outlets 41 and 46 inparallel to tube 47.

The steam generated in evaporation chambers 10 and l 1. respectively. issucked through openings 39 and 44 in the hollow drum 3. The steam passesthrough the spider [5 which permits axial flow of vapor therethroughinto a gas compressor 8. The gas compressor 8 may either be a multistagefan, or other type ofsingle or multi-stage gas compressor. Thecompressor 8 may be driven by a separate motor. or as shown in this cni(il l bodiment, driven by the main drive motor 6 through the gear train7.

The gear train 7 which is merely illustrative has a drive gear Sl whichis keyed to the shaft 5. The drive gear 51 drives the gear 52 on theidler shaft 53. The idler shaft 53 has keyed to it a gear 54 whichdrives the gear 55. The gear 55 drives the high speed drum 56 whichsupports and drives multi-stage compressor fans 57 and 58.

To prevent salt water particles from being sucked into the hollow drum 3from the evaporation chambers 10 and 11, gravity drain mesh, fiberstrainer, or centrifugal louvered droplet slingers 59 and 60,respectively, may be used to prevent salt water particles from enter ingthe hollow drum 3 and the compressor 8. By using the slingcrs 59 and 60,the salt water particles are slung upon impacting the slingers inclinedslats radially outwardly and back toward the rotating disc 2, while thesteam passes between the slats of the slingcrs 59 and 60 into the hollowdrum 3 and into the compressor 8. The compressor 8 raises the pressureand temperature of the steam. as well as the condensation temperature,and in general, results in the steam becoming superheated. This higherpressure steam at its higher temper ature is removed from the compressor8 through the discharge duct 61 into condensing chamber 12. This highpressure steam condenses on the surfaces of rotating discs 2 which formthe condensation chamber 12. The condensed fresh water is slung from therotating discs 2 into annular fresh water channels 62 and 63. The freshwater is removed from fresh water channels 62 and 63 by radial wateroutlet orifices 64 and 65, respectively. The fresh water is collected inthe tube 66 which is passed into tri-fluid counter-flow heat exchanger32. The hot fresh water is removed from the heat exchanger 32 as coolerwater by the tube 67 where it is passed through a venturi 68 throughoutlet 69 to a pure water storage tank (not shown).

Since super-heated steam is difficult to condense in spite of the lowenergy required to super-heat the steam. and to provide intercooling ofthe compressor 8 to increase the efficiency of the compressor close toadiabatic conditions, a small quantity of fresh water is metered out oftube 66 by the valve 70 and sprayed in an extremely fine mist by sprayring or set of jets 71 into the inlet of the compressor 8. The finespray mist of fresh water de-super-heats the steam as it passes from thehollow drum 3 into the compressor 8, and brings the steam down intemperature to saturation temperature. Alternatively. water may besprayed into the compressor 8, in which the rotary action of the bladeswill further divide the water into fine particles for easier evaporationduring the long path length through the compressor 8 and its dischargeduct 61. The addition of water to the compressor 8 serves both to desuper-heat the steam and to remove some of the waste heat energy of thecompressor 8 caused by friction. turbulence, or other energy losses. toincrease the compressor efficiency. decrease compressor powerrequirements, and increase the mass flow of steam through the compressor8. The saturation temperature of the steam at the compressor outlet 61is higher than the saturation temperature under the pressure conditionsat the inlet of the compressor 8. Accordingly. the condensing sides ofthe disc 2 are hotter than the sides where evaporation takes place. Thisresults in not heat flow from the steam in the condensing chamber I2 tothe steam in evaporation chambers I and II.

While an overall general description of the rotary dc salting engine ofthe present invention has been set forth. there are several mattersrelating to specific aspects of the present invention which should beset forth. The first aspect is directed to the rotating circular disc 2which are mounted on and driven by the hollow drum 3. In the embodimentof FIG. I. there are two discs 2 which are tied together for structuralintegrity and geometric stability.

Around the periphery of the disc 2 are disc seal collector channels 40,62, 63 and 45, respectively. Because fluid is forced by centrifugalforce into the col lector channel, this arrangement provides a gas andliquid seal which relies solely on the hydrodynamic forces created bythe disc rotation. Referring to FIGS. 2 and 3 for more detail, the disc2 in FIG. 2 has a bifurcated terminating portion with one leg 73extending into the channel 62. The concentrated brine solution which isslung from the disc 2 into the channel 40 forms a set ofcounter-rotating helical vortices in the channel 40 until it iswithdrawn out of tangential orifice 41. The fluid as it begins to fillthe channel 40 will be removed as it en ters the orifice 41 whichcontrols the fluid level in the channel. In the same manner. the freshcondensed water will be slung off the disc 2 into the channel 62 and beremoved from the tangental orifice 64. The portion 75 is a rise betweenthe channels 40 and 62 which prevents fluid from passing from onechannel to the other.

Referring to FIG. 3, there is an alternative arrangement of a disc sealcollector. In this modification, the disc is flat at its periphery. Thechambers and I2 are identical to that described in FIG. 2, as well asthe channels and 62 and the orifices 41' and 64'. respectively. In thismodification, the wiping seal is contained in the rotary disc housingstructure and one por tion 73' extends from the limits of the channel40' whereas a second portion of the seal 74' extends from the channel62'. The rotary disc extends into a depression 75 in this modification.

The fluid slung off the discs 2 flows into and fills the annularchannels in rotary disc chamber housing 4. The fluid, which is underpressure due to its high centrifugal force. and which is rotating in thechannels as a single clockwise vortex. or dual counter-rotating helicalvorti ces caused by disc-induced rotation. acts in conjunction with thedisc running in the channel as a pressure seal between chambers 10 andI2 and chambers 11 and I2. The level of fluid in the channels isadjusted by the position of outlet orifices relative to the bottom ofthe channel. The pressure of the rotating fluid is communicated to thefluid outlet so that the disc, in effect. also acts like a second pumpof a centrifugal type. If this pressure is too high because of excessivefluid rotational velocity resulting in energy waste. backward curvedgrooves can be cut in the disc surface to reduce the fluid rotationalspeed.

Another specific aspect of the present invention re latcs to the removalof dissolved or entrained gas in the system. Referring to FIG. 4, thereis shown an example of a liquid phase device whereas in FIG. 5, there isan e\amplc of a vapor phase device.

Referring to FIG. 4, and utilizing the same reference numerals as inFIG. I. the degasser 24 of FIG. 4 has an inlet tube 23. and an outlettube 25. A flow control uti free 76 is in the liquid inlet tube 23 tothe degasser 24. Circular peripheral flow spill trays 77 and center flowspill trays 78 are stacked alternately and spaced vertically within thedegasser 24. A float 79 pivoted from the rocker arm and support 80 andhinged to the gas valve actuating rod 81 operates a valve 82 in the gasoutlet 83. The pum suction applied by pump 27 through outlet tube 25applies suction through the dc gasscr 24 through restriction orifice 76.The impedances of the lines, filters and sea water lift requirementsbefore degasser 24 create the suction heat which causes the dissolvedgas in the sea water to appear as small gas bubbles and evolve from thefluid it cycles radially in and out in thin sheets over the spill trays77 and 78. The evolved gases which are lighter than the fluid fill thetop of degasser 25 from which they are sucked out through outlet 83 dueto the vacuum created as the brine solution passes through the venturi49. Float 79 assures that the pump is always supplied with liquid andnot gas since it closes the passage to the pump when the liquid leveldrops and opens when the liquid rises to a set level.

Referring to FIG. 5. the specific aspects of the degasser 30 areillustrated. Using the same reference numerals as in FIG. I, introducedinto vapor phase degasser 30 is a mixture of evolved gas and vaporpicked up by a T 84 shown in FIG. I at the outer peripheral region ofcondensing chamber 12. Due to the higher density of the evolved gas ascompared to the vapor, the gas is concentrated near the periphery of therotating disc due to the centrifugal force created by the rotation. Thismixture passes through the T 84 into a tube 85 and metering valve 86which adjusts and optimizes the flow into the vapor degasser 30 to limitvapor loss with asso ciated system energy loss. Sea water is introducedby the tube 29 into the degasser 30 whereas the water exits the degasser30 by the tube 31. In the degasser 30, the vapor and gases from tube 85flow through the helical tube coil 87 immersed in the liquid coolingannulus 88. The vapor is condensed into liquid or fresh water andcollecting at the bottom of the degasser 30 whereas the evolved gas iscooled and collects in the gas space above the liquid. A liquid float 89opens a valve 90 in the outlet line 91 when liquid or water collects,and which is drawn out through the fresh water line 67 by the venturi68. Thermostatic gas valve 92 in the tube 93 allows any collected cooledgases to be removed from the system, but would block the flow of the hotvapor should there be any in the gas space.

From the above description, it is obvious that both liquid and vaporphase degassers should function with a negligible energy requirement andconserve the energy available in the fluids supplied to them. This isnot true with other known degassing devices which either require powerconsuming pumps or throw away energy by discharging heated vapor withthe evolved gas.

Referring to FIG. 6, wherein another embodiment of the present inventionis illustrated. a rotary dcsalting device IOI has a single rotating discI02 which extends from a hub I03. The rotating disc I02 rotates in arotating disc chamber housing 104. The rotating disc I02 is attachedthrough the hub 103 to an armature shaft I05 of a dri\e motor I06. Thearmature shaft 105 also drncs a gear train 107 which in turn drives thecompressor fan of the compressor 108.

As shown in the embodiment of FIG. I), there is a sin gle rotatingcircular disc I02 which is mounted on and driven by the armature shaftwhich is connected to the disc by means of the hub 103. The rotatingdisc 102 as it rotates in rotating disc chamber 104 forms an evaporationchamber 109 on one side of the rotating circular disc 102 and acondensing chamber 1 10 on the other side of the disc 102. In thisembodiment of the present invention, collection channel means 111 areattached to the periphery of the disc 102. The collec tion channel means111 has one channel 112 to collect the brine from the evaporationchamber 109, and a second channel 113 which collects the fresh waterfrom the condensing chamber 110. The details of the collection channelmeans 111 and each of the channels 112 and 113 are seen in more detailin FIG. 7. Inserted into each of the collection channels is one or morestationary scooping devices 114 and 115, scooping device 114 being inchannel 112 and scooping device 115 being in channel 113. The scoopingdevices 114 and 115 are fashioned in such away as to minimize the flowdisturbances associated with placing a stationary object in a movingstream of fluid. A shield (not shown) may be placed on the scoops 114and 115 in order to divert any fluid which is splattered by the scoopback onto the disc 102 or into the collection channels 112 or 113. Byremoving the fluids in the manner just described. the power lossassociated with shearing of the water between a stationary channel walland a moving disc does not occur. hi this embodiment. however. the sealmeans between the evaporation chamber 109 and the condensing chamber 110is a wiping seal 116 which is held within a slot in the rotating discchamber housing 104 by means of block 117. The wiping seal 116 is placedon the side of the rotating disc 102 on the high pressure or condensingchamber 1 10 so as to be forced into contact with the collection channelmeans 111. Alternatively. the seal means in this embodiment may be astationary member (not shown) held by the rotating disc chamber housing104 which extends from the housing into the fluid in one of the channelsin channel means 111 and seals chamber 109 from chamber 110. Preferably,however. channel means 111 would have a separate channel filled withfluid for the stationary member to extend into so as not to disturb thefluids within channels 112 or 1 13. Such a seal means provides ahydrodynamic seal similarly as described with regard to the embodimentof FIG. 1.

in order to allow the heat transfer from the condens ing chamber 110 tothe condensing chamber 109 to be as great as possible. the disc 102 isconstructed from very thin, highly heat conductive material. in order toincrease the structural integrity of this thin disc 102, a system ofsupporting spokes may be used as is shown in FIG. 8. Two sets ofspokcsare shown eminating from the central hub 103 of the disc 102. Spokes 118are at tached to a mid-radius locus of the disc 102 while an other setof spokes 119 are attached at the disc periphcry. The spokes 119 have anadjustment capability through adjustment means 120. This adjustmentcapability is used to move the periphery of the disc 102 back and forthin an axial direction in order to adjust the pressure with which thewiping seal 116 bears on the collection channel means 111 and toeliminate wobble of the disc 102. This adjustment may also he used to rcduce the leakage and the power drawn by the wiping seal 116.

1n the embodiment of FIG. 6. the flow of water to the disc 102 isdifferent from the embodiment set forth hereinbcfore. In this embodimentone or more mid-disc distributors 121 are attached by a plurality ofpost means 122 to the rotating disc 102 as shown in more detail in FIG.9. Referring to FIG. 9, water is fed from tube 123 tangentially into thetop of a Ushaped member 124 which forms the outer ring 124' of thedistributor 121 at a rate preferably at or near the rotational speed ofthe disc 102 so that the water is essentially laid into ring 124. Theplurality of post means 122 are at tached at the top of the U of thcU-shapcd member 124. Extending from the bottom of the U of the U shapedmember 124 is a skirt means 125 which forms a second ring 125'. Whenouter ring 124 is full, the water overflows into a second ring 125'which also fills and overflows. By the time that the water overflowsring 125" it is uniformly distributed within the distributor 121 byattaining the same rotational velocity as the disc 102 through shearbetween the water and the rings 124' and 125' and becomes evenlydistributed around the ring by eentrifugally induced hydrostatic forcesthus capable of being equally supplied to the disc 102 in all radialdirections. The water overflowing the second ring 125' flows onto anextended lip means 126 which is tapered to a knif edge. The knife edgeis inset into a depression region 127 of the disc 102. \Nhen the waterreaches the knife edge it is slung by centrifugal force into the wall ofthe depression 127 in the disc 102. Once the water has contacted thedisc 102, adhe sion forces causes it to remain in contact with the disc102 and the centrifugal force causes the water to move radially outwardin a thin, uniform film. The mid-disc distributor 121 being attached tothe disc 102 is rotat ing at the same speed as the disc 102 whichuniquely promotes even distribution of the water on the disc 102 andenables high heat transfer on the disc 102 due to the thin. uniform filmwhich results. W'ater is shown as being fed to the disc 102 in only twolocations in FIG. 6, but as many distribution places as may be practicalmay be used. Only the minimum amount of water rcquircd to cover the discarea between distributors 121 is fed at each distributor location. By sodoing. the film thickness inside the final distributor is, on theaverage. significantly thinner than with a single central feed point.Hence. the resistance to heat transfer caused by the excess filmthickness is overcome.

To illustrate the use of the rotary desalting device 101 a process forthe desalination of sea water will be described. The sea water is drawninto the rotary desalting device 101 through an intake to a strainer 128to remove any solid material. The sea water thereafter may pass into aliquid phase dcgasser 129, the details of which may be set forthhercinbefore. The water is drawn into the rotary desalting device 101 bymeans of pump 130 which may be driven by motor 106 through gear train107. After the water is drawn through pump 130, the water is passedthrough a unique ion-exchange water pretreatment system 131 to removedissolved or suspended material that the process will not otherwiseremove. The treated water then passes through pipe 132 into a tri-fluidcounter-flow heat exchanger 133. The sea water is heated to near itsboiling temperature in the heat cschangcr 133 and then passes out of theheat exchanger 133 by pipe 134 into a motor water jacket 135 wherein theheat from the motor I06 is picked-up by the water. \Nater from the motorwater jacket [35 flows to a heat rcscnoir 136 containing a heater Thus.heat can be easily added to the water as it passes through heatreservoir 136. especially during start-up. The water exiting the heatreservoir I36 flows by line 137 where it is divided into two streams.One stream 138 is controlled by a preset valve 139 which allows afraction of the water to be supplied to the middisc distributor 121. Bythis means a portion of the water during the start-up provideslubrication in the form of the sea water. to get to the wiping seal I I6and hastens systems start-up by restricting the water flow duringstart-up. The other stream 140 is controlled by a thermostatic valve 141which remains closed until the water reaches operating temperature.

After start-up has been achieved and the system has reached operatingequilibrium. the heated sea water leaves the heater resevoir I36 andflows through both lines 138 and 140. the thermostatic valve 141 beingopen during system equilibrium. The heated sea water flowing throughline 138 is introduced by a tube 123 to the mid-disc distributor 121 andflows onto the disc 102 as has been described hereinbefore. Waterflowing through line 140 is passed through a tube 142 directed into thedepression 143 in the hub 103 of the disc 102. As the depression 143fills, the water begins to over flow. The overflow of the water takesplace uniformly, supplying water to the disc I02 equally in all radialdircctions. This uniform overflow gives rise to a uniform distributionof water on the disc 102. As can be seen by the description of thedistribution of the water on to the rotating disc 102, a very thin filmof water is formed uniformly on the entire rotating disc 102 increasingthe heat transfer due to the extremely thin water film thickness.

As the water is introduced to the rotating disc 102 due to the heatbeing applied to the opposite side. the

temperature of the disc in the evaporating chamber 109 is higher thanthe boiling point for sea water. at the pressure existing in the chamber109, and accordingly. some of the sea water is converted to steam. Theremaining sea water on the disc I02 becomes a more concentrated brinesolution. Because of the centrifugal force imparted to the brinesolution. the brine solution is slung toward the periphery of the disc102 where it fills the collection channel 112 of the collection chan'nel means 111. The brine solution is removed from channel 112 by meansof scooping device 114 and removed by a tube 144 where it passed by lineI45 into the tri-fluid counter-flow heat exchanger 133. The brinesolution is cooled in the heat exchanger 133 and then removed by line146.

The steam generated in evaporation chamber 109 is passed through tube147 into the gas compressor 108. The gas compressor 108 may either be amulti-stage fan. or other type of single or multi-stage gas compressor.A compressor 108 may be driven by a separate motor. or as shown in FIG.6. driven by the main drive motor 106 through the gear train 107.

The steam after compression is in a super heated condition when it exitsthe compressor 108. It exits through a pipe 148 where it is passed intothe condensing chamber 110. In the pipe 148 may be a spiral tube (notshown) wherein a small amount of fresh water may be introduced into thesuper heated steam leaving the compressor 108. The water flowing throughthe spiral tube of the de-super heater is heated by the steam whichflows around the tube. The water thus enters the stream of super heatedsteam in pipe 148 as heated water or a mixture of water and saturatedsteam and is readily entrained by the moving stream which has lost itssuper heat energy to the fresh water by the time it reaches thecondensation chamber 110. The advantage of such a de-super heater isthat it does not necessitate introducing the de-super heating water as afinely divided sprayv The compressed steam which enters the condensation chamber is restrained from passing around the periphery of therotating disc 102 into the evaporation chamber 109 by the wiping seal116. The steam condenses on the rotating disc 102 where it is slung bythe centrifugal forces to the periphery of the rotating disc I02 and thewater collection channel 113. The scooping device picks up the water andpasses it through tube 114 where it is passed by line 150 to thetri-fluid counter-flow heat exchanger 133. The cooled fresh water isremoved from the heat exchanger 133 through pipe 151 where it is passedto a pure water storage tank (not shown).

Whereas the prior art discloses distillation operations with rotatingcones and curved drums at low rotational speeds producing centrifugalaccelerations of the water of 10s of gs the present invention permitsl00s or 1.000s of gs of centrifugal acceleration of water because of thedesign of the plane disc. seal and water distribution system. This highacceleration coupled with the unique water distribution system causes avery thin. uniform water film on the disc. which in turn produces a heattransfer coefficient of about 5 times that claimed in publicationsrelated to the prior art. For example the design of the presentinvention has permitted a disc heat transfer coefficient of 8.700 BTU/fthr. F for a [6 inch diameter disc rotating at L725 RPM which produces680 gs at the perimeter. A 6 foot diameter disc rotating at this speedwould produce 2.500 gs at the perimeter and a somewhat higher heattransfer coefficient. Since a contiguous film was obtained in practiceon a 16 inch diameter disc turning at 3,450 RPM with a perimetercentrifugal acceleration of 2.720 gs which is approximately equal to thegs on the 6 foot disc. the 6 foot disc may be operated at the l .725 RPMspeed. Because of the difficulty of spinning flexible curved drums orcones at high speed with their attendant vibration and distortionproblems under load. it is not believed that the high gs are possiblewith the prior art. since for good heat transfer. the drums or conesmust necessarily be thin and are necessarily limited in size.

The nature and objects of the present invention having been completelydescribed and illustrated. and the best mode thereof contemplated setforth. What I wish to claim as new and useful and secure by LettersPatent is:

I. A liquid distributor which comprises: a U-shaped means forming anouter ring; a plurality of post means for attaching said U-shaped meansto a disc which are attached to the top of the U of said U-shaped means;

skirt means extending from the bottom of the U of said U-shaped means onthe same side said post means which forms a second ring; and

extending lip means extending from said skirt means as a tapered knifeedge.

2. A liquid distributor according to claim I which furthcr includes athin disc.

3. A liquid distributor according to claim 1 which further includes atube which feeds the fluid tangentially into said outer ring.

4. A liquid distributor for distributing a liquid on a surface whichcomprises:

a circular skirt extending away from said surface with one edge of saidskirt terminating adjacent said surface in spaced relationship therebyforming a lip for evenly distributing said liquid onto said surface;

an outer annular wall attached to said skirt at a point removed fromsaid lip of said skirt. said outer annular wall extending from saidskirt inwardly toward the center of the circle defined by said skirt;

at least one inner annular wall attached to said skirt at a pointintermediate said outer annular wall and said lip said inner annularwall extending from said skirt inwardly toward the center of the circledefined by said skirt;

and means to rotate said circular skirt about its axis.

5. The liquid distributor of claim 4 wherein the height of said innerannular wall is less than the height of said outer annular wall.

6. The liquid distributor of claim 5 including means to feed liquid intothe space intermediate said outer an nular wall and said inner annularwall whereby liquid fills said space overflows said inner annular wallonto said skirt and flows to said lip 7. The liquid distributor of claim6 wherein said lip is a tapered knife edge,

8. The liquid distributor of claim 7 wherein said circular skirt isattached to said surface by a plurality of post means.

9. The liquid distributor of claim 8 wherein said surface has a circulardepression adjacent said lip and said tapered knife edge is insertedinto said circular depresslon,

(ill

It). The combination of a disc with at least one liquid distributormeans for distributing liquid on the surface of said disc wherein saidliquid distributor means includes a circular skirt extending away fromthe surface of said disc with one edge of said skirt terminatingadjacent said disc thereby forming a lip for evenly distributing saidliquid onto the surface of said disc;

an outer annular wall attached to said skirt at a point removed fromsaid lip of said skirt. said outer annular wall extending from saidskirt inwardly toward the center of the circle defined by said skirt;

at least one inner annular wall attached to said skirt at a pointintermediate said outer annular wall and said lip, said inner annularwall extending from said skirt inwardly toward the center of the circledefined by said skirt;

and means to rotate said circular skirt about its axis 11. Thecombination of claim 10 wherein the height of said inner annular wall isless than the height of said outer annular wall 12. The combination ofclaim 11 including means to feed liquid into the space intermediate saidouter annular wall and said inner annular wall whereby liquid fills saidspace overflows said inner annular wall onto said skirt and flows tosaid lip.

13. The combination of claim l2 wherein said lip is a tapered knifeedge,

14. The combination of claim I]: wherein said circular skirt is attachedto said disc by a plurality of post means,

15. The combination of claim 14 wherein said disc has a circulardepression adjacent said lip and said ta pered knife edge is insertedinto said circular depres sion

1. A liquid distributor which comprises: a U-shaped means forming anouter ring; a plurality of post means for attaching said U-shaped meansto a disc which are attached to the top of the U of said U-shaped means;skirt means extending from the bottom of the U of said U-shaped means onthe same side as said post means which forms a second ring; andextending lip means extending from said skirt means as a tapered knifeedge.
 2. A liquid distributor according to claim 1 which furtherincludes a thin disc.
 3. A liquid distributor according to claim 1 whichfurther includes a tube which feeds the fluid tangentially into saidouter ring.
 4. A liquid distributor for distributing a liquid on asurface which comprises: a circular skirt extending away from saidsurface with one edge of said skirt terminating adjacent said surface inspaced relationship thereby forming a lip for evenly distributing saidliquid onto said surface; an outer annular wall attached to said skirtat a point removed from said lip of said skirt, said outer annular wallextending from said skirt inwardly toward the center of the circledefined by said skirt; at least one inner annular wall attached to saidskirt at a point intermediate said outer annular wall and said lip, saidinner annular wall extending from said skirt inwardly toward the centerof the circle defined by said skirt; and means to rotate said circularskirt about its axis.
 5. The liquid distributor of claim 4 wherein theheight of said inner annular wall is less than the height of said outerannular wall.
 6. The liquid distributor of claim 5 including means tofeed liquid into the space intermediate said outer annular wall and saidinner annular wall whereby liquid fills said space, overflows said innerannular wall onto said skirt and flows to said lip.
 7. The liquiddistributor of claim 6 wherein said lip is a tapered knife edge.
 8. Theliquid distributor of claim 7 wherein said circular skirt is attached tosaid surface by a plurality of post means.
 9. The liquid distributor ofclaim 8 wherein said surface has a circular depression adjacent said lipand said tapered knife edge is inserted into said circular depression.10. The combination of a disc with at least one liquid distributor meansfor distributing liquid on the surface of said disc wherein said liquiddistributor means includes a circular skirt extending away from thesurface of said disc with one edge of said skirt terminating adjacentsaid disc thereby forming a lip for evenly distributing said liquid ontothe surface of said disc; an outer annular wall attached to said skirtat a point removed from said lip of said skirt, said outer annular wallextending from said skirt inwardly toward the center of the circledefined by said skirt; at least one inner annular wall attached to saidskirt at a point intermediate said outer annular wall and said lip, saidinner annular wall extending from said skirt inwardly toward the centerof the circle defined by said skirt; and means to rotate said circularskirt about its axis.
 11. The combination of claim 10 wherein the heightof said inner annular wall is less than the height of said outer annularwall.
 12. The combination of claim 11 including means to feed liquidinto the space intermediate said outer annular wall and said innerannular wall whereby liquid fills said space, overflows said innerannular wall onto said skirt and flows to said lip.
 13. The combinationof claim 12 wherein said lip is a tapered knife edge.
 14. Thecombination of claim 13 wherein said circular skirt is attached to saiddisc by a plurality of post means.
 15. The combination of claim 14wherein said disc has a circular depression adjacent said lip and saidtapered knife edge is inserted into said circular depression.